Arc flash and flash fire resistant fabrics, and garments made therefrom, need to meet several ASTM specifications and should be tested according to ASTM test methods provided. The ASTM specifications related to arc flash and flash fire resistant fabrics and garments include ASTM D751: “Standard Test Methods for Coated Fabric”; ASTM F1959: “Standard Test Method for Determining the Arc Rating of Materials for Clothing”; ASTM F2733: “Standard Specification for Flame Resistant Rainwear for Protection Against Flame Hazards”; ASTM D6413/D6413M: “Standard Test Method for Flame Resistance of Textiles (Vertical Test)”; ASTM F1891: “Standard Specification for Arc and Flame Resistant Rainwear”; and ASTM F1930: “Standard Test Method for Evaluation of Flame Resistant Clothing for Protection Against Flash Fire Simulations Using an Instrumented Manikin”.
Numerous prior art patents and disclosures relate to creating a fabric with attached polyvinylchloride sheets. The relevant patents and publications are discussed below.
U.S. Pat. No. 4,139,613 to Hefele discloses a process for the patterned deposition of powdered thermoplastic adhesive materials on the outer surface of a surface form. This process is for the patterned deposition of powdered thermoplastic adhesive materials on the outer surface of a textile or other porous-flexible surface form, wherein there is first insertion raked in a pattern of depressions formed in an engraved component an adhesive powder material and then on this powder a further adhesive powder material is insertion raked in the depressions, so that both the powder layers superposed one on the other are taken up by the surface form which is positioned on the engraved component. The surface form of a polyvinylchloride sheet does not have a porous surface. Further, the adhesive powder is not indicated to be polyvinylchloride.
U.S. Pat. No. 4,970,111 to Smith, Jr. discloses flame retarding fusion bonded non-woven fabrics. This fire resistant, non-dripping, fusion bonded, non-woven fabric or fabric structure comprising a synergistic blend of about 35 to 80% by weight of chlorine-containing polymeric fibers, about 2 to 25% by weight of stabilized polyacrylonitrile fibers and about 10 to 55% by weight of a fire retarding polyester binder. The non-woven fabric of chlorine containing fibers is made from fibers of polyvinylidene dichloride, chlorinated polyethylene, and polyvinyl chloride. The chlorine containing non-woven fabric is not a meta-aramid liner and is not attached to a PVC sheet.
U.S. Pat. No. 7,921,471 to Mordecai, et al. discloses a protective coat for use by emergency responders. This coat is for use by emergency responders, such as firefighters. Certain aspects of the coat include a barrier resistant liner for protection against chemical and biological agents, a compression zone that can improve safety when working in hazardous areas, and a flame resistant shell including zippered sleeves that can facilitate the donning of protective gloves. The barrier liner is made from material selected from the group consisting of urethanes, PTFE, neoprene, natural and synthetic rubber, para-aramids, and polyamides. There is no non-woven liner attached to the barrier liner.
U.S. Pat. Nos. 8,156,576 and 8,359,675 to Terrell disclose flash fire and chemical resistant fabric and garments. The flash fire and chemical barrier composite fabric comprises a flame resistant fibrous basic layer, a radiant heat and chemical permeation barrier. The barrier includes a metalized polymeric chemical permeation resistant layer film. A clear heat sealable outer film layer overlays over the radiant barrier and forms a heat sealable outer surface of the composite fabric. The flame resistant fibers are chosen from fiberglass, carbonized fibers, rayon, cotton, wool and aramid fibers, aromatic polyamide, polyester, or their blends. The radiant heat and chemical permeation barrier layer is chosen from polyvinylidene chloride, ethylene vinyl acetate, chlorinated polyethylene, polyethylene, low density polyethylene, linear low density polyethylene, high density polyethylene, nylon, polyvinyl alcohol, polyester, polytetrafluoroethylene, fluorinated ethylene propylene, propylene, polyvinyl chloride copolymer, acrylic, acrylonitrile, and ethylene vinyl alcohol. The radiant heat and chemical permeation barrier layer is a co-extruded multi-layer film with a metalized layer adhered to its top and/or bottom. The flash fire resistance is improved by the metallized film coated radiant heat and chemical permeation barrier layer. A thermal expanding adhesive layer dispersed between the flame retardant fiber and a metalized chemical barrier layer. This thermal expanding adhesive layer prevents ignition of the outer clear thermoplastic layer when exposed to flash fire. The fabric has five functional layers, as shown in the figures and the Description of Embodiments of the Invention, which are bonded together using the adhesive to form the fabric and the flexibility of the fabric is expected to be poor.
U.S. Patent Application No. 20110262704 to Rock et al. discloses flame resistant composite fabrics. The flame resistant composite fabric includes a first flame resistant fabric layer, a second flame resistant fabric layer, and a barrier layer that bonds the first flame resistant fabric layer to the second flame resistant fabric layer. The barrier layer is capable of withstanding temperature of 500° F. for at least 5 minutes without substantial changes in the integrity of the flame resistant composite fabric. Both the first flame resistant fabric layer and the second flame resistant fabric layer are formed of flame resistant treated fibers, yarns, and/or fabric. As shown in FIG. 3, the adhesive 24 is indicated to be polyvinylchloride bonding first and second flame resistant fabric layers 21, 22. The flame resistant fabric does not contain a sheet of polyvinylchloride.
U.S. Patent Application No. 20080176065 to Hirschmann et al. discloses a flash resistant material. This arc flash resistant material includes a para-aramid non-woven material substrate and a polyurethane film containing approximately 10-40% by weight of antimony oxide (Sb2O3, Sb2O5) and decabromodiphenyl oxide containing a high level of aromatic bromine laminated to a first surface and a second surface of the para-aramid non-woven material substrate. The arc flash resistant material may be breathable and include antistatic properties. The arc flash resistant material is lightweight, exhibits an exceptionally high level of protection from an arc flash hazard, and possesses a low particulate level that is required for clean room applications. As shown in FIG. 1, the non-woven fabric substrate is surrounded on both sides by flame resistant polyurethane film. The non-woven substrate contains para-aramid fibers not flame resistant meta-aramid (Nomex) fibers. A polyvinylchloride sheet is not attached to the non-woven substrate.
Publications and patents related to the properties of polyvinylchloride are also included below.
The web page at http://engineering.ucsb.edu/˜saurabh/Presentations/Solvents.pdf details a thesis in which solvent properties are linked with corresponding polymers. As shown in FIG. 7, polyvinylchloride is soluble in methylene chloride, ethylene dichloride, and tetrahydrofuron. Since acetone is on the boundary of the circle in the Hansen graph of solubility, the solubility of PVC in acetone is expected to be minimal. The following patent disclosures detail the effect of molecular weight of polyvinylchloride in acetone indicating that high molecular weight (>18,000) do not dissolve in acetone while low molecular weight polyvinylchloride (4000-16,000) dissolves.
U.S. Pat. No. 2,427,513 to Spessard discloses a process of dispersing copolymer of vinyl chloride and vinyl acetate in a ketone and hydrocarbon dispersant. Some of such resins are virtually insoluble in the common organic solvents at ordinary temperatures, while sufficient amounts of others to be practical cannot be dissolved in the solvents without the solutions becoming unduly viscous or gelling. When articles are coated with dilute solutions, multiple coats must be applied to secure the requisite coating thickness, and large volumes of solvents are necessarily handled. Resins of the first class include delta polyvinyl chloride, while the second class of resins includes beta polyvinyl chloride, copolymers of vinyl chloride with vinyl acetate, which have molecular weights above 16,000, as determined by Staudinger's method, and vinyl chloride contents within the range of 90 to 99%, as well as copolymers of vinyl chloride with maleate esters and acrylate esters, such as dibutylmaleate, ethyl acrylate, methyl acrylate, and methyl methacrylate of substantially the same combined vinyl chloride content and molecular weight. Resins, such as the copolymers of vinyl chloride with acrylonitrile, containing from 45 to 80% vinyl chloride, which are soluble in acetone but insoluble in many other solvents, and the copolymers of vinyl chloride with vinylidine chloride have solubility characteristics inter mediate to these classes, depending on their molecular weight. All of such resins may be characterized by being at least swellable by acetone, but acetone has no greater solvent action on them than it does on a copolymer of vinyl chloride with vinyl acetate having a molecular weight of 16,000 and a vinyl chloride content of 90%. A 20% solution of this resin in a mixture of 50 parts of acetone and 50 parts or toluene by volume has a viscosity of 31 seconds at 25° C.
U.S. Pat. No. 2,517,356 to Pierre discloses solutions of polyvinyl chloride in a mixture of acetone and perchloroethylene. It has been known that the solubility of vinylchloride polymers in organic solvents varies considerably according to the degree of their polymerization, Thus, polymers of low molecular weight are completely soluble in acetone, while polymers of high molecular weight do not dissolve in acetone even at boiling temperature and they do not dissolve in most of the other organic solvents either. This lack of solubility limits to a great extent the uses of vinylchloride polymers of high molecular weight, which, as known, are the most interesting technically. Example 1 of the patent application indicates that a vinyl chloride polymer having a molecular weight of 18,000 is insoluble in acetone at ordinary room temperature. The molecular weight is calculated b y using Staudingers formula Nsp/c=Km×M, where Nsp is the specific viscosity measured at 20 C of a solution of 2 g./liter of the polymer in a solvent consisting of equal volumes of acetone and carbon disulfide. Km is a constant of the solvent amounting to 2.7×10−4; c is the concentration in grams per liter and M the degree of polymerization.
U.S. Pat. No. 2,646,414 to Gillespie discloses a polyvinyl chloride polymer dispersion. A low-molecular-weight vinyl chloride polymer (or mixture of polymers) shows an appreciable solubility in ketones by weight, and which is a vinyl chloride polymer (inclusive of copolymers) of a molecular weight between 5,000 and 16,000 and having in excess of about 60% by weight combined vinyl chloride in the molecule. Acetone is the preferred volatile organic liquid since acetone produces compositions of a higher solids content for a given viscosity.
Based on the foregoing, there exists a need in the art for a flexible arc flash and flash fire resistant polyvinylchloride fabric and garments using the fabric that have a non-woven meta-aramid (Nomex) fiber liner bonded to a polyvinylchloride sheet. The arc flash and flash fire resistant properties of polyvinylchloride sheet bonded to fire resistant non-woven substrate of meta-aramid fibers allows the creation of a lightweight flexible single layer garment.